That does not prove anyone nowdays refers to Czechs or gypsies as Bohemians. Bohemia is not even made fun of within czech republic, there are no special negative stereotypes or oppression made to it. They call themselves czechs, they don't tend to refer to themselves as bohemians.
It just ... exists. And contains capital.
And the word in English means what I wrote and not whatever you imagine it to mean.
Strange, my father's entire family (emigrated from the region in the late 1800's) still refer to themselves as Czech and Bohemians almost interchangeably. It has fallen out of use, but "bohunk" was an ethnic slur that was semi-common for most of my grandparents lives.
To be clear, I am not saying that the word bohemian is used as a slur. I am merely finding it ironic that people who have qualms about things like "master" in git or "microagressions" have no problem using a word that was used in France to make light of any genetic eastern Europeans. "bohemian" as an artsy, free living, dirt poor hippy utterly erases centuries of history of a real people (not even the people they thought it applied to).
It just ... exists. And contains capital.
And the word in English means what I wrote and not whatever you imagine it to mean.